Recent years have witnessed an upward _______ of trade and comme

Recent years have witnessed an upward _______ of trade and commerce between China and Britain.
A、trend
B、incentive
C、system
D、preoccupation
【正确答案】：A
【题目解析】：trend趋势；incentive动机，刺激；system系统；preoccupation全神贯注，入神。句意：近年来，中英之间的贸易呈上升趋势。